package shixhun;

import java.util.Scanner;

public class ss{
     public static void main(String[] args){
         Scanner sc = new Scanner(System.in);
         int n= sc.nextInt();
          if(n==1){
              System.out.println("素数");
         } else if (n==2) {
              System.out.println("素数");
          }else if(n%2==0){
              System.out.println("不是素数");
          }else{
              for(int i=3;i<n/2;i++)
                  if (n % i == 0) {
                      System.out.println("不是素数");
                  }
          }

     }
}
